Process for producing stable dyeings.



TED STATES PATENT OFFICE.

ARTHUR SCHLEGEL, OF MANNHEIM, GERMANY, A.ND KARL PFISTER, OF PHILADEL- PHIA, PENNSYLVANIA, ASSIGNORS T BADISCHE ANILIN & SODA FABRIK, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, A. CORPORATION.

PROCESS FOR PRODUCING STABLE DYEINGS.

No Drawing.

ble Dyein'gs, of which the following is, a.

specification.

In the specification of Patent No. 893,384 one of us has described and claimed a process of dyeing with vat coloring matters of the anthracene series by applying a paste of the said coloring matters to the fiber and then treating the material with an alkaline reducing agent in the presence of water and alkali. For this purpose the textile material,

after bleaching or extracting with boiling water, was treated with a paste of the coloring matter either by padding or printing, and the material was then either dried or rolled up without being dried. In a subsequent operation the material was treated, after having been so prepared, with a solution or suspension of an alkaline reducing agent. In the application of the coloring matter it could be used with or without the addition of a thickening agent. When operating as described in the example of the said Patent No. 893,384 it is directed that the cotton should be treated in the alkaline reducing bath for about 30 minutes, that is to say, the material is allowed to pass forward and backward through the bath, for instance in a jigger.

We have now invented an improved method of carrying out the said process, whereby it is not necessary to treat the material for such a long time in the reducing bath, a sufiicient fixation of the dyestufi being attained by a single passage of the material, to which the coloring matter has been applied, for a very shorttime through an alkaline reducing bath which, however, in this case must be much more concentrated with regard to hydrosulfite. In this way, the dyer is in a position to arrange the two steps,

' namely the application of the dyestuif to the material and the passage through the reducing bath, in a continuous manner and to carry outthe whole process easily and in a shorter space of time and thus to produce a more dyed material in a given time.

The new process is carried out as follows.

Specification of Letters Patent.

Patented Dec. 15, 1914.

a thickening agent, or may contain caustic soda, or both, is applied to the goods in a padding machine, the squeezing rollers of which are so arranged that the material absorbs about 80% of its weight of the dye suspension. After one single treatment as described, the material (either without being dried or rolled up, or after having'been dried and rolled up, or dried without being rolled up) is passed into the developing solution which consists of a warm strong hydrosulfite solution containing caustic alkali. After a short single passage through this liquid, the material is rolled up on a suitable roller. The reduction of the coloring matter and its fixation on the fiber becomes completed while the material is on this roller. These operations can be carried out in an ordinary jigger in which a small trough provided with a roller is inserted. to hold the hydrosulfite solution, For ordinary working, this trough need not contain more than 2 gallons of solution and as the material removes the solution from the trough, a sulficient fresh quantity is continuously added.

By way of example, we give the following quantities that can be applied in carrying out this invention,-but the invention is not confined to this example.

For dyeing about 110 lbs. of cotton cloth, that is to say 12 pieces, prepare a thin paste from about 27 lbs. of a vat coloring matter suspended in the liquid uniformly by stir-' ring. A thickening agent may also be added .to assist inthe maintenance of a uniform suspension. During this treatment, the material should absorb about ll'gallons of the suspension. The alkaline reducing bath is prepared from 6 to 8 lbs. of commercial sodium hydrosulfite, 4.5 lbs. of caustic soda and 21 gallons of water. This solution should have a temperature of about 160 F.

in the tank in which it is stored, so that its temperature in the trough in which it is applied to the material is about 140 F. The goods are passed once through this solution as described and absorb about 11.5 gallons of the liquid.

Now what we claim is The process for producing stable dyeings I by passing the material to be dyed through a paste or a vat coloring matter of the anthracene series and then fixing the coloring matter on the fiber by a single short passage through a Warm alkaline hydrosulfite solution containing about three to four parts scribing witnesses.

of sodium hydrosulfite per hundred parts '15 of water.

In testimony whereof wehave hereunto setour hands in the presence of two sub- 

